Electronic mail (commonly referred to as “email”) is a ubiquitous medium used to communicate messages, documents, and other information between different people. Like traditional postal mail, a user has an email “address” to which communications may be directed, and from which emails may be sent. Emails include within them this address information, as well as the content intended to be communicated to the recipient, whether a short informal note, a business proposal, multimedia content (e.g., pictures and Uniform Resource Locators (URLs)), or myriad other information. When a user composes and then sends an email, the user's computer communicates with software to enable the transmission of the email to the identified recipient(s). In some cases, delivery of an email may be delayed or may fail due to network congestion, problems with one or more email servers, or an incorrectly-entered email address. Such a delay or failure can cause an automated response message to be sent to the sender to indicate the delay or failure.